Step size for controlling stepper motor

To determine the current you need, you first have to know the torque you need. That is a function of the external system that only you know. Once you know the torque you look in the table and see what current is required to generate that torque. If you can tolerate a lower torque for holding versus moving, then you can have a lower hold current than run current.

Keep in mind that motion inevitably eats up some torque due to friction, which actually helps for the holding case. The back EMF of the motor will also reduce the apparent voltage applied to the windings as a function of speed. Stepper motors are rather inefficient, so their back EMF is usually not that big. You can measure it yourself by looking at the open circuit voltage when mechanically spinning the motor at a known speed. That's how much less voltage the motor "sees" at that speed than what you apply.

I have tried to figure this out on my own without looking at the drive circuit as a challenge. After finding this article, I now am fairly convinced that my motor is built after a 5-phase design.

The picture says it all really. 10 windings = 5 phases.

So since it is not a 2-phase motor, it is inherently bi-polar as opposed to uni-polar which some 2-phase designs are. Also it will typically have higher resolution than 2-phase motors. For example some motors have 500 steps per rev which gives 360/500 = 0.72° degrees per step. The resolution depends on the number of teeth.

There are many ways to drive it (see article above), and in most respects it is superior to the 2-phase design, except Torque at low speeds.